LADEE
NASA announced that LADEE has crashed into the surface of the moon on April 18. NASA

NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) has completed its mission and the spacecraft crashed into the lunar surface on Thursday. LADEE’s lunar impact went as planned, though slightly ahead of schedule, as NASA officials had predicted the spacecraft would crash into the moon closer to April 21.

LADEE was launched on Sept. 7, 2013, and it began orbiting the moon on Oct. 6. The spacecraft has been collecting data for more than five months, beginning on Nov. 10, and it started its 100-day primary science mission orbiting around the moon’s equator on Nov. 20, according to NASA. LADEE completed its primary science objective on March 5, and the space agency extended the spacecraft’s mission for an additional 28 days.

LADEE did not have enough fuel to escape the moon's orbit or continue with its science mission. The spacecraft’s final orbital maintenance maneuver on April 12, its 22nd, put LADEE into a low-altitude orbit, just one mile above the surface of the moon, and a natural descent into the lunar surface began. LADEE survived the total lunar eclipse on April 15. Before LADEE crashed into the lunar surface, the spacecraft reached speeds of 3,600 miles per hour, and it most likely broke apart before impact.

Rick Elphic, LADEE project scientist at NASA’s Ames Research Center, said in a statement, “There’s nothing gentle about impact at these speeds -- it’s just a question of whether LADEE made a localized craterlet on a hillside or scattered debris across a flat area. It will be interesting to see what kind of feature LADEE has created.”

LADEE’s main mission was to collect data on the lunar atmosphere, including its structure and composition, and to collect lunar dust samples. Data collected by the spacecraft could also solve the mystery of the presunrise glow observed by Apollo astronauts.

NASA had some fun with the scheduled LADEE lunar impact and to commemorate it launched the “Take the Plunge” challenge, which asked members of the public to guess when the spacecraft would crash into the moon. For those who guessed between 12:30 and 1:22 a.m. EDT (9:30 and 10:22 p.m. PDT) NASA will send out a special certificate.

Based on preliminary data, it is believed LADEE may have crashed into the east rim of Sundman V crater, located on the far side of the moon. After determining the exact impact site, NASA plans to sending the Lunar Reconnaissance Orbiter (LRO) to observe LADEE’s final resting place.